Digital audio player capable of playing digital audio data through existing cassette tape player

ABSTRACT

A digital audio player comprises a semiconductor memory device for rewritably recording digital audio data and a digital audio reproducing unit for converting the digital audio data into analogue audio data and for reproducing the analogue audio data. The digital audio player comprises a casing which has the same shape as that of a cassette tape and which contains the semiconductor memory device and the digital audio reproducing unit. The digital audio reproducing unit comprises a digital/analogue converter for converting the digital audio data recorded in the semiconductor memory device into the analogue audio data and an output head for outputting the analogue audio data converted by the digital/analogue converter to a reproducing head of a cassette tape player for reproducing the analogue audio data recorded in the cassette tape.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a digital audio player used forreproducing digital audio data through a cassette tape player widelypopularized for reproducing analogue audio data from a cassette tape asa recording medium for recording analogue data.

[0002] Recently, the digital audio player for reproducing or playing thedigital audio data recorded in a semiconductor memory device through aspeaker or a headphone is spreading. The digital audio data is recordedby the use of such compression encoding format as an MP3 (MPeg (MPEG:Motion Picture Expert Group) audio layer 3). Particularly, the digitalaudio player of portable type such as to be provided with a battery andplay the digital audio data through the headphone.

[0003] However, the cassette tape player only for the cassette tape isstill major as an audio player used in a home or a car of a consumer.Furthermore, the possession number of the cassette tape player for eachconsumer or for each home may be plural.

[0004] Therefore, all the cassette tape players of the consumer arenever changed into the digital audio player for a while. In other words,it may be necessary for changing a large number of the cassette tapeplayers into the digital audio players of high cost and a long time.

[0005] After a CD (Compact Disc) using a CD-DA (CD-Digital Audio) formatbegan to be saturated, an adapter for playing the audio data from suchCD player of the portable type through such cassette tape player of amobile type (so called as a cassette car stereo set) is developed andnow used popularly.

[0006] The adapter has a casing which has the same shape as that of thecassette tape, an output head, and a cable having a plug connector. Theoutput head is arranged in the casing and can output analogue audio datato a playing head of the cassette tape player by using electromagneticinduction. The plug connector can stick in a socket connector of the CDplayer or the like. Thus, the cable can connect between the output headand the CD player through the plug connector.

[0007] It is not to say that the adapter can be connected to not onlythe CD player but also the digital audio player. The adapter is reallyconnected to the digital audio player of the portable type and thedigital audio data can be played through the cassette car stereo set.Furthermore, by using the adapter, the audio data from such MD (MiniDisc) player and LCD (Liquid Crystal Display) television set of theportable type can be also played through the cassette car stereo set.

[0008] However, wiring operation for connecting between the digitalaudio player and the adapter is really hard and troublesome and it isreally difficult to secure a space for arranging the digital audioplayer wiring with the wiring mentioned above in the car.

SUMMARY OF THE INVENTION

[0009] It is therefore an object of this invention to provide a digitalaudio player capable of playing digital audio data through an existingcassette tape player, of cutting down troublesome wiring work forconnecting between the cassette tape player and the digital audioplayer, and of leaving out a space for arranging the digital audioplayer.

[0010] The other objects, features, and advantages of this inventionwill become clear as the following description proceeds.

[0011] A digital audio player to which this invention comprises asemiconductor memory device for rewritably recording digital audio dataand a digital audio reproducing unit for converting the digital audiodata into analogue audio data and for reproducing the analogue audiodata. The digital audio player comprises a casing which has the sameshape as that of a cassette tape and which contains the semiconductormemory device and the digital audio reproducing unit. The digital audioreproducing unit comprises a digital/analogue converter for convertingthe digital audio data recorded in the semiconductor memory device intothe analogue audio data and an output head for outputting the analogueaudio data converted by the digital/analogue converter to a reproducinghead of a cassette tape player for reproducing the analogue audio datarecorded in the cassette tape.

[0012] According to an aspect of this invention, the digital audioplayer further comprises a self electric-generation unit contained inthe casing. The self electric-generation unit generates electric powerby electromagnetic induction caused by driving power of a motor which isprovided in the cassette tape player for driving a hub or a tape of thecassette tape, said self electric-generation unit supplying electricpower to the digital audio reproducing unit.

[0013] According to the other aspect of this invention, the digitalaudio player further comprises a digital audio recording unit forconverting the analogue audio data into the digital audio data and forrecording the digital audio data in the semiconductor memory device. Thedigital audio recording unit comprises an erasing instruction detectinghead for detecting as an erasing instruction signal an erasing signalwhich is for use in erasing the analogue audio data recorded in thecassette tape and which is generated by an erasing head provided in acassette tape recorder, an input head for receiving the analogue audiodata which should be recorded in the cassette tape and which areproduced by a recording head provided in the cassette tape recorder, andan analogue/digital converter, when the erasing instruction detectinghead detects the erasing instruction signal, for converting the analogueaudio data from the input head into the digital audio data and forrecording the digital audio data in the semiconductor memory device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a block diagram showing a structure of a digital audioplayer according to a first embodiment of this invention; and

[0015]FIG. 2 is a block diagram showing a structure of a digital audioplayer according to a second embodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Now, preferred embodiment of this invention will be describedwith reference to drawings.

[0017] First Embodiment

[0018] Referring to FIG. 1, a digital audio player according to a firstembodiment of this invention has, as like to the conventional digitalaudio player of a portable type, a semiconductor memory device 20 forrewritably recording digital audio data and a digital audio reproducingunit 30 for for converting the digital audio data recorded in thesemiconductor memory device 20 into analogue audio data and reproducingthe analogue audio data.

[0019] The digital audio player further has a casing 40 having the sameshape and size as those of a conventional cassette tape and whichcontains the semiconductor memory device 20 and the digital audioreproducing unit 30.

[0020] Furthermore, the digital audio player has a control unit 10 fortotally controlling the operations of the digital audio player. Thecontrol unit 10 has a CPU (Central Processing Unit) 11 and a gate array12.

[0021] The digital audio reproducing unit 30 has a decoder 31, a DAC(Digital/Analogue Converter) 32, a head amplifier 33, and an output head34.

[0022] The decoder 31 decompresses and decodes the digital audio data(compressed and encoded by an MP3 format) recorded in the semiconductormemory device 20. The DAC 32 converts the digital audio datadecompressed and decoded into the analogue audio data. The headamplifier 33 amplifies the analogue audio data so that the output head34 sufficiently responds to the analogue audio data.

[0023] The output head 34 outputs the analogue audio data converted bythe DAC 32 and amplified by the head amplifier 33 to a reproducing headof the cassette tape player (not shown) for reproducing the analogueaudio data recorded in the cassette tape. To be more concrete, theoutput head 34 has an approximate structure to a recording head of acassette tape recorder for recording the digital audio data to thecassette tape. The output head 34 is provided with a suspension 34 a forsuspending the output head 34 on the casing 40 so that the output head34 moves with corresponding to the reproducing head of the cassette tapeplayer and is positioned at an applicable position to the reproducinghead.

[0024] The semiconductor memory device 20 may be a card typestandardized in shape, size, and electric circuit such as Smart media,Compact flash, Memory stick, and Multimedia card. Furthermore, thesemiconductor memory device 20 may be a type memorized an ID datatherein. The semiconductor memory device 20 is contained in the casing40 so as to be removable from the casing 40.

[0025] The digital audio player further has a battery 60, contained inthe casing 40, supplying electric power to the control unit 10 and thedigital audio reproducing unit 30. The battery 60 may be a dry cell typeor a rechargeable cell type. In FIG. 1, wirings between the battery 60and portions to be supplied with the electric power from the battery 60are omitted in drawing. The battery 60 may be contained in the casing 40so as to be removable from the casing 40. Consequently, if the battery60 is rechargeable and removable from the casing 40, the battery 60removed from the casing 40 is individually charged by an exclusivebattery charger. On the other hand, if the battery 60 is rechargeableand not removable from the casing 40, the battery 60 contained in thecasing 40 is charged by a battery charger through a wiring (not shown)connecting the battery charger and the digital audio player. If thebattery 60 is also rechargeable and not removable from the casing 40,the battery 60 contained in the casing 40 may be charged by the batterycharger in a condition that the casing 40 is put on a cradle (not shown)for holding the casing therein.

[0026] In order to digitally and rewritably record the digital audiodata to the semiconductor memory device 20, the digital audio player mayfurther have a digital data interface (not shown). The digital datainterface is contained in the casing 40, interfacing between the digitalaudio player (the semiconductor memory device 20) and an electricapparatus such as a personal computer and a portable cellular phone. Forexample, the digital data interface is a USB (Universal Serial Bus)interface or an IEEE1394 (Institute of Electrical and ElectronicsEngineers 1394) interface.

[0027] Furthermore, the digital audio player further has a headphoneamplifier 35, a headphone socket 36, and a user interface 50 containedin the casing 40.

[0028] The headphone amplifier 35 amplifies the analogue audio dataconverted by the DAC 32 so that a headphone 200 sufficiently respond tothe analogue audio data. The headphone socket 36 makes the headphone 200removably connecting to the digital audio player and interfaces betweenthe headphone amplifier 35 and the headphone 200 so that the analogueaudio data are output to the headphone 200.

[0029] The user interface 50 serves to operate various operations of thedigital audio player by the user of the digital audio player. Namely,the user interface 50 is provided with operation switches 51 and adisplay 52. The operation switches 51 controls various operation such aspower on/off, audio play, audio stop, track selection, audiofast-forward and audio rewind, volume adjusting. The display 52 isstructured by such as a liquid crystal display and displays variousinformations such as track number, playing time, track title, andbattery capacity. Thus, the digital audio player can be, as like to theconventional digital audio player of the portable type, used (play audiothrough the headphone 200) independently from the cassette tape player.

[0030] When the digital audio player having a structure that has beendescribed above is inserted in the cassette tape player such as the carstereo set instead of the cassette tape, the digital audio data recordedin the semiconductor memory device 20 are reproduced or played throughan amplifier and a speaker or a headphone of the cassette audio player.

[0031] Second Embodiment

[0032] Referring to FIG. 2, a digital audio player according to a secondembodiment of this invention has, as like to the digital audio player ofthe first embodiment, the semiconductor memory device, the digital audioreproducing unit, the casing 40 having the same shape and size as thoseof the conventional cassette tape, the control unit provided with theCPU and the gate array, the battery 60 contained in the casing 40 forsupplying the electric power to the control unit and the digital audioreproducing unit, and the user interface provided with the operationswitches and the display. Parts provided with no symbol in thedescription mentioned above are also omitted in drawing in FIG. 2. Thedigital audio reproducing unit also has, as like to the firstembodiment, the decoder, the DAC, the head amplifier, the output headprovided with the suspension, the headphone amplifier, and the headphonesocket.

[0033] Furthermore, the digital audio player has a selfelectric-generation unit contained in said casing 40. The selfelectric-generation unit generates electric power by electromagneticinduction caused by driving power of a motor (not shown), provided inthe cassette tape player, for driving a hub or a tape of the cassettetape and supplies electric power to the control unit and the digitalaudio reproducing unit 30.

[0034] In the second embodiment, the motor of the cassette tape playeris that for driving the hub. Although the self electric-generation unitcan supply the electric power to the control unit and the digital audioreproducing unit 30 any directly or indirectly through the battery 60,the self electric-generation unit in the second embodiment supplies asthe latter.

[0035] The self electric-generation unit has an electric-generator 70and an inverter circuit 80. The electric-generator 70 is provided with ahub portion having an annular shape and is rotatably arranged in thecasing 40, a permanent magnet 71 having an annular shape and is attachedto the hub portion, a core 73 having an annular shape and is rigidlyattached to the casing 40 around the hub portion, and a plurality ofcoils 72 annularly attached to the core 73 so as to surround thepermanent magnet 71. Lead wires of the coils 72 are connected to aninput port of the inverter circuit 80. An output port of the inverter 80is connected to the battery.

[0036] When the digital audio player having a structure that has beendescribed above is inserted in the cassette tape player such as the carstereo set instead of the cassette tape, the digital audio data recordedin the semiconductor memory device are reproduced through the amplifierand the speaker or the headphone of the cassette audio player.Furthermore, the permanent magnet 71 is rotated with the hub portion bythe motor for driving the hub of the cassette tape player. Consequently,the coils 72 generates electric current by the electromagneticinduction. The electric current is converted to voltage by the inverter80. The electric power from the inverter 80 is supplied to the battery.Thus, frequency of replacement of and/or charge on the battery 60 can bereduced.

[0037] Third Embodiment

[0038] A digital audio player according to a third embodiment of thisinvention also has, as like to the digital audio player of the first orthe second embodiment, the semiconductor memory device, the digitalaudio reproducing unit, the casing having the same shape and size asthose of the conventional cassette tape, the control unit provided withthe CPU and the gate array, the battery contained in the casing forsupplying the electric power to the control unit and the digital audioreproducing unit, and the user interface provided with the operationswitches and the display.

[0039] Furthermore, the digital audio player has a digital audiorecording unit, contained in the casing, for for converting the analogueaudio data into the digital audio data and for recording the digitalaudio data in the semiconductor memory device.

[0040] The digital audio recording unit has an erasing instructiondetecting head, an input head, a ADC (analogue to digital converter), anerasing instruction detecting head, and an encoder.

[0041] The erasing instruction detecting head detects as an erasinginstruction signal an erasing signal which is for use in erasing theanalogue audio data recorded in the cassette tape and which is generatedby an erasing head provided in a cassette tape recorder. The input headinputs the analogue audio data output, for recording the digital audiodata in the cassette tape, from a recording head provided in thecassette tape recorder. The ADC converts the analogue audio data fromthe input head into the digital audio data. The encoder compresses andencodes the digital audio data by the MP3 format to be record in thesemiconductor memory device.

[0042] When the erasing instruction detecting head detects the erasinginstruction signal, the ADC converts the analogue audio data from theinput head into the digital audio data and the encoder compresses andencodes the digital audio data. Thus, the analogue audio data are recordas the digital audio data in the semiconductor memory device.

[0043] The output head may serve double duty as the input head. However,the digital audio player must comprise a switching circuit for switchingwhich the analogue audio data are transmitted to the output head or fromthe input head. The DAC can also serve double duty as a part or allparts of the ADC.

[0044] When the digital audio player having a structure that has beendescribed above is inserted in the cassette tape recorder instead of thecassette tape, the analogue audio data are converted into the digitalaudio data and recorded in the semiconductor memory device. For example,when the digital audio player is inserted in the cassette tape recorderhaving such audio source as the CD, radio, and a microphone, the audiodata from the CD, the radio, or the microphone can be recorded in thesemiconductor memory device.

[0045] While this invention has thus far been described in conjunctionwith the embodiments thereof, it will readily be possible for thoseskilled in the art to put this invention into practice in various othermanners. For example, the shape and the size of the casing of thedigital audio player is not limited to only the cassette tape andtherefore may be another analogue recording medium such as amicro-cassette tape. Furthermore, the semiconductor memory device of thedigital audio player is not limited to only the semiconductor type andtherefore may be another digital memory device such as a hard diskdrive.

What is claimed is:
 1. A digital audio player comprising a semiconductormemory device for rewritably recording digital audio data and a digitalaudio reproducing unit for converting the digital audio data intoanalogue audio data and for reproducing the analogue audio data; whereinsaid digital audio player comprises a casing which has the same shape asthat of a cassette tape and which contains said semiconductor memorydevice and said digital audio reproducing unit; said digital audioreproducing unit comprising a digital/analogue converter for convertingthe digital audio data recorded in said semiconductor memory device intothe analogue audio data and an output head for outputting the analogueaudio data converted by said digital/analogue converter to a reproducinghead of a cassette tape player for reproducing the analogue audio datarecorded in the cassette tape.
 2. A digital audio player as claimed inclaim 1, wherein said semiconductor device is standardized so as to havea card shape and is removable from said casing.
 3. A digital audioplayer as claimed in claim 1, wherein said digital audio player furthercomprises a battery contained in said casing, said battery supplyingelectric power to said digital audio reproducing unit.
 4. A digitalaudio player as claimed in claim 3, wherein said battery is removablefrom said casing.
 5. A digital audio player as claimed in claim 1,wherein said digital audio player further comprises a digital datainterface contained in said casing, said digital data interfaceinterfacing between said semiconductor memory device and an electricapparatus for digitally and rewritably recording the digital audio datato said semiconductor memory device.
 6. A digital audio player asclaimed in claim 1, wherein said digital audio player further comprisesa headphone socket and a user interface contained in said casing, saidheadphone socket interfacing between said digital/analogue converter anda headphone so that the analogue audio data converted by saiddigital/analogue converter are output to the headphone, said userinterface serving to operate various operations of said digital audioplayer by the user of said digital audio player.
 7. A digital audioplayer as claimed in claim 1, wherein said digital audio player furthercomprises a self electric-generation unit contained in said casing, saidself electric-generation unit generating electric power byelectromagnetic induction caused by driving power of a motor which isprovided in the cassette tape player for driving a hub or a tape of thecassette tape, said self electric-generation unit supplying electricpower to said digital audio reproducing unit.
 8. A digital audio playeras claimed in claim 3, wherein said self electric-generation unitindirectly supplies the electric power to said digital audio reproducingunit through the battery.
 9. A digital audio player as claimed in claim1, wherein said digital audio player further comprises a digital audiorecording unit for converting the analogue audio data into the digitalaudio data and for recording the digital audio data in saidsemiconductor memory device; said digital audio recording unitcomprising: an erasing instruction detecting head for detecting as anerasing instruction signal an erasing signal which is for use in erasingthe analogue audio data recorded in the cassette tape and which isgenerated by an erasing head provided in a cassette tape recorder; aninput head for receiving the analogue audio data which should berecorded in the cassette tape and which are produced by a recording headprovided in the cassette tape recorder; and an analogue/digitalconverter, when said erasing instruction detecting head detects saiderasing instruction signal, for converting the analogue audio data fromsaid input head into the digital audio data and for recording thedigital audio data in said semiconductor memory device.